This has a lot of potential!
First off, I liked the audio and the graphics! The sfx were simple but effective! I wasn't a big fan of the lighting.
The faustian bargain was a cool feature!
The cannon is really satisfying to shoot and land.
As others have pointed out, the laser misfiring was off putting. Though I did like the alternation between claws, and landing it felt nice.
The claw is really hard to use! I think I would rather if it was aimed at the direction of the mouse, as it stands, I couldn't use it without getting hit!
But those issues disappear in cheat mode, because the combination of all three weapons overwhelms whatever's in front of you regardless, and that feels really good! It sort of reminds me of when I got an OP build in Risk of Rain. Man, being a cheater never felt so good!
I almost forgot to try that mode, it changed my perspective on the game, it's honestly a lot of fun! Personally I would either make that the default, or allow the player to build up to that throughout the game. But that's me :)
Very fun entry!